Heat and blower control for a dryer



March 15, 1966 c. A. COBB ETAL 3,239,945

HEAT AND BLOWER CONTROL FOR A DRYER Filed Oct. 10, 1962 s Sheets-Sheet 1AT RNEYS March 15, 1966 c, COBB ET AL 3,239,945

HEAT AND BLOWER CONTROL FOR A DRYER Filed Oct. 10, 1962 3 Sheets-Sheet 2A TTORNE) March 15, 1966 c. A. COBB ET AL HEAT AND BLOWER CONTROL FOR ADRYER 5 Sheets-Sheet 5 Filed Oct. 10, 1962 i I T l I l I52 United StatesPatent 3,239,945 HEAT AND BLOWER CONTROL FOR A DRYER Clifton A. Cobb,James T. Williams, and William F. Gourdeau, St. Joseph, Miclr, assignorsto Whirlpool Corporation, St. Joseph, Mich, a corporation of DelawareFiled Oct. 10, 1962, Ser. No. 229,575 8 Claims. (Cl. 34-45) Thisinvention relates generally to drying systems and dryers and moreparticularly relates to an apparatus for drying materials wherein thethermal energy input rate is simultaneously changed to match a changedflow volume of air when the ratio of motor to blower speed isselectively varied.

Although the principles of the present invention are of generalapplicability, a particularly useful embodiment is provided in a dryingsystem of a laundry appli ance or dry cleaner wherein a blower is usedto drive a stream of temperature-conditioned air through a treatmentzone. In accordance with prior art procedures, dryer apparatus forclothes or for dry cleaning apparatus generally utilize a single speedblower motor which directs a stream of air through the treatment zone inaccordance with a fixed flow volume. In accordance with the principlesof the present invention, a single speed electric motor is provided,however, the blower shaft is particularly characterized by a multiplepulley groove driving hub wherein the multiple grooves are of differentdiameter and the pulley belt is selectively shiftable between thegrooves, thereby to vary the speed of the impeller of the blower andhence adjust the flow volume of the air flowing through the treatmentzone. It is further contemplated by the present invention that thethermal energy input rate be simultaneously changed with the blowerspeed adjustment, thereby matching the thermal energy input rate to thechanged flow volume of air.

It is an object of the present invention to provide a blower apparatuswhich has a capacity for changing the flow volume of an air streamdirected through the treatment zone.

Another object of the present invention is to provide an apparatus fordrying wherein the thermal energy input rate can be matched to a changedhow volume of air.

Yet another object of the present invention is to provide a blower for adryer wherein the blower shaft has a driving hub characterized bymultiple pulley grooves of different diameter and wherein a pulley beltmay be selectively shifted between the grooves to vary the flow volumeof air discharged by the blower.

Yet another object of the present invention is to provide a controldevice for simultaneously effecting regulation of an electric circuitand for mechanically shifting a speed changing device.

Many other features, advantages and additional objects of the presentinvention will become manifest to those versed in the art upon makingreference to the detailed description which follows and the accompanyingsheets of drawings in which a preferred structural embodiment of alaundry appliance incorporating the principles of the present inventionis shown by way of illustrative example and in connection with which thepresent invention may be effectively practiced.

On the drawings:

FIGURE 1 is a rear view of a dryer incorporating the principles of thepresent invention;

FIGURE 2 is an enlarged fragmentary view with 3,239,945 Patented Mar.15, 1966 parts removed showing additional details of the pulley beltshifting mechanism of the present invention;

FIGURE 3 is a cross-sectional view of the blower impeller takengenerally on line Ill-III of FIGURE 1;

FIGURE 4 is a fragmentary view showing additional detals of constructionof the pulley belt shifting mechamsm;

FIGURE 5 is a view similar to FIGURE 4 but taken on a plane shifted toillustrate additional details of construction of the belt-shiftingmeans;

FIGURE 6 is a circuit diagram illustrating the control circuitassociated with the dryer of FIGURE 1;

FIGURE 7 is a cross-sectional view taken on line VII-VII of FIGURE 8;and

FIGURE 8 is a cross-sectional view taken on line VIIIVIII of FIGURE 7,FIGURES 7 and 8 showing the control device for simultaneously effectingcontrol of the circuit and the belt-shifting means.

As shown on the drawings:

The principles of the present invention are advantageously incoporatedin and practiced with a laundry dryer apparatus shown generally inFIGURE 1 at 10 wherein the machine is shown as having a casing 11 with aconsole panel 12 and a so-called control tower 13 on one side thereof.

The rear of the machine is shown with a back wall removed, thereby toexpose the operating components of the dryer apparatus 10 and asillustrated in FIGURE 1, there is provided a single speed electric motor14. In an exemplary form of dryer construction, the single speed motorcan take the form of an electric motor having a normal operating drivingspeed of 1725 rpm. and has a drive shaft 16 to which is attached apulley 1'7 cooperating with a blower pulley belt shown at 18.

The motor 14 also drives a belt 19 which is trained over the outerperiphery of drum 20 which is mounted for rotation on axially disposedshaft 23 so as to extend into the interior of casing 11, therebyproviding a clothes treatment zone. Shaft 23 is fixedly attached to thebulkhead 31. Ribs 21 and hub 22 provide stiffening means for bulkhead31.

The laundry apparatus 10 incorporates the usual air system through whicha stream of ventilated air is directed. In this connection, the airsystem includes a vertical tempering conduit 26 which is mounted on therear of bulkhead 31, the conduit 26 having a temperature-conditioned airoutlet 27 which leads to the interior drum 20. Thermal energy is addedto the air stream in the tempering conduit 26, thereby totemperature-condition the air which passes through air inlet 2611. Ablower shown generally at 30 is located on the rear of bulkhead 31 anddraws moisture-laden air from the interior of drum 20, and dischargesthis stream of moisture-laden air through vent 32 which extends from theblower outlet conduit 30a through the partial back panel 28.

An exhaust outlet which coincides with the blower mlet is also providedfor the treatment zone in the bull head 31. Vent 32 may be connected toa suitable pipe 1f the machine is vented to the outside atmosphere orelse the discharging air may vent directly into the space in which thedryer is located.

Although the laundry drying appartus 10 is of a type which could beadvantageously employed with either a source of heat comprising a gasburning means, or electrical resistance elements, the present exemplaryform of the invention is described for purposes of illustration inconnection with a machine employing electrical resistance-type heatingelements wherein two separate heating elements 33 and 34 and locatedwithin the tempering conduit 26 (see FIGURE 6). For example, the heatingelements 33 and 34 could comprise elements of 3600 watts and 2000 watts,respectively.

In accordance with the principles of the present invention, it iscontemplated that the volume flow of air driven through the treatmentzone be selectively variable. To effect that end, a speed-changingmechanism is associated with the blower.

In FIGURE 3 there is shown a blower impeller 36 having plural vanes 37carried on a hub 38 fastened as at 39 to the end of a shaft 40. Theshaft is journaled in a bearing sleeve means 41 retained within abearing housing 42 cushioned in a rubber mount 43 carried by a doublewall portion 44 which mounts on the blower 38 which in turn mounts onthe rear of bulkhead 31 of the casing 11. The bearing housing 42 isformed with a lubricant reservoir 46 preferably filled with alubricant-impregnated packing material and the reservoir is closed by aclosure shown at 47.

On the outside of the rear bulkhead 31 and on the end of the shaft 40opposite the impeller 36, there is provided a driving hub 50 retained incorotatable assembly with shaft 40 by means of a set screw 51. The hub50 is particularly characterized by the formation in the peripheralsurface thereof of multiple pulley grooves, for example, 52 and 53,which are of different diameters, the groove 52 having a smallerdiameter than the groove 53.

In order to selectively shift the pulley belt 18 between the multiplepulley grooves 52 and 53, a pulley shifting mechanism is provided,different aspects of which are illustrated in FIGURES 1, 2, 4 and 5.

The pulley shifting mechanism as indicated generally at 68 and morespecifically includes a bracket having a mounting leg 61 secured byfasteners 62 to the outermost of the walls 44 adjacent the hub 50. Thebracket includes a second leg 63 which extends at right angles to theleg 61 and carries a pivot pin 64 to which is connected a rotatable orpivotable disk 66.

The disk 66 has projecting radially outwardly therefrom two separateangularly spaced arms or projections 67 and 68. The projection 68carries a tapered roller 69 in journaled relation and it will be notedupon inspecting FIGURE that the projection 68 with the roller 69 thereonis somewhat longer than the corresponding projection 67. The projection67 has a belt-engaging surface 70 on one side thereof and is concavelyrecessed as at 71 on the other side thereof, thereby to engage a stop 72which can be adjustably set by virtue of having formed therein acentrally disposed elongated slot 73 and an adjustable fastener 74.

Also projecting radially outwardly from the disk 66 is a lever arm 76having a connecting lug 77 to which is connected the inside wire 78 of aBowden cable 79 leading to a remotely located actuating device. TheBowden cable is retained by a clip 80 secured as at 81 to one of thewalls 44.

As will be evident from inspecting FIGURE 5, the roller 69 and theprojection 67 are angularly disposed to confine in the included angletherebetween the pulley belt 18. Thus, if the disk 66 is pivotallydisplaced in a clockwise direction the roller 69 will engage the pulleybelt 18 and will tend to shift the belt 18 out of the groove 52 and intothe groove 53. On the other hand, if the disk 66 is rotated in acounterclockwise direction, the projection 67 will tend to push thepulley belt 18 out of the groove 53 and into the groove 52.

In FIGURE 6, the control circuit for the dryer apparatus is illustrated.The control circuitry is shown associated with a three-wire sourceincluding lines L L and a neutral line N.

In the control circuit of FIGURE 6, there is shown a temperatureselector switch 90 having a movable selector element 91 movable from anoff or air contact position 92, a low or delicate temperature contactposition 93 and a high or normal temperature contact position 94.

In circuit with the low temperature contact 93, there is an operatingthermostat 96 and in circuit with the high temperature contact 94 thereis an operating thermostat 97. It will be understood that thethermostats 96 and 97 can be set for different operating temperatures,for example, the low temperature thermostat could be set for 135 F.,While the thermostat 97 could be set for 165 F.

The circuit also includes a safety thermostat which is indicated at 98and which develops the function of protecting the apparatus againstoverheating at any time.

The circuit also includes a door switch shown generally at 100 includinga movable element 101 operated to its open position upon opening of thedoor to stop the machine.

In order to effect simultaneous control of the thermal energy input rateand the blower speed or volume flow of air, a novel actuating mechanismis provided which is shown in FIGURES 7 and 8. The actuating mechanismincludes an electric switch shown generally at and having a box-shapedhousing 111 open on one side and spanned on the open side by aninsulator wafer 112 carrying electrically conductive terminals 113 and114. The housing 111 is carried on a two-piece U-shaped bracketincluding a first leg 116 and a second leg 117 fastened together byrivets 118.

The bight portion of the U-shaped bracket 116, 117 is suitably aperturedby a slot 119, thereby to confine the opposite ends of a spring takingthe form of a strip member bent to form a loop 120 and including ahorizontally disposed leg 121 extending upwardly from the bight portionto provide an engagement surface for a lug 122 carried on a lever arm123 fastened in corotatable assembly with a switch shaft 124.

The shaft 124 is journaled for rotation in suitable apertures formed inthe leg 117 and the leg 116 and actuates a movable switch element withinthe switch housing 111 for controlling electric circuitry associatedwith the terminals 113 and 114.

In order to mount the actuator on the control tower 13 in an accessibleposition for regulation by an operator, the leg 117 is fastened by a lug126 and a fastener 127 to a bracket 128 by fasteners 129 to a wall 130of the control tower 13. The shaft 124 has an end portion formed with afiat 131 extending outwardly through an aperture 132 in the wall 130 anda manual actuating knob 133 is fastened to the shaft 124 so thatmanipulation can be effected from the front of the machine.

In FIGURE 8, the lever 123 is shown formed with an opening 134 by meansof which the wire 78 of the Bowden wire 79 can be attached.

In operation, when the knob 133 is angularly shifted, the shaft 124 isconcurrently rotated, thereby actuating the electrical elements withinthe switch housing 111 and simultaneously angularly shifting the lever123 so that the wire 78 in the Bowden wire 79 is actuated to move thelever arm 76 on the speed-shifting mechanism 60.

The action of the electrical switch 110 will be understood uponreferring to the wiring diagram of FIG- URE 6.

When the knob 133 is positioned so that a high input or thermal energyinput rate is available, the belt 18 is automatically shifted from thegroove 53 by the mechanical action of the Bowden wire 79 which rotatesthe disk 66 and, in turn, the projection 67 moves the belt into thegroove 52, thereby providing a high speed for the blower impeller 36.Simultaneously, the shaft 124 closes both sets of contacts, shown at113, 113a and 114, 114:: (FIG- URE 6) to energize the heater 34 and alsoto light an indicator light shown at 140. Both heaters 33 and 34 will becombined to give a maximum heat input. If the temperature selectorswitch 90 is set so that movable element 91 contacts contact 94, hightemperature thermostat 97 will regulate the temperature conditioning ofthe air stream.

When the knob 133 is positioned so that a low heat input is available,the shaft 124 moves the lever 123 and the Bowden cable 79 transmits themovement to the lever 68, thereby moving the roller 69 against the belt18 and shifts the belt out of the groove 52 into the groove 53 to reducethe speed of the blower impeller 36.

Simultaneously, the contacts 113, 11311 and 114, 114a are opened,thereby reducing the heat input by breaking the electrical circuit tothe heating element 34.

The dryer control apparatus also includes a timer motor shown at 150 andwhich actuates through appropriate mechanical means 151 appropriateswitching means 152 which are normally closed during a drying cycle,thereby effecting energization of the main drive motor 14. There is thusprovided in a clothes drying machine including a heat source and an airtranslation means driven by a motor means through a belt a controlapparatus wherein the belt may be shifted to effect an increase or adecrease in the speed of the air translation means simultaneously withthe increase or decrease of the heat output of the heat source andthereby effecting a correlation or matching of air translation speedwith heat input to the dryer.

Although various minor modifications might be suggested by those versedin the art, it should be understood that we wish to embody within thescope of the patent warranted hereon, all such modifications asreasonably and properly come within the scope of our contribution to theart.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

1. A clothes dryer comprising, a single speed electric drive motor,means forming a treatment zone in which materials are to be dried, meansincluding a blower for directing a stream of air through said treatmentzone, variable heat input heating means for applying thermal energy atdifferent selected input rates to the air stream, a multiple speedtransmission connecting said motor and said blower for selectivelydriving said blower at different motor to blower speeds, thereby to varythe volume flow of the air stream and control means regulating saidheating means between said different input rates to vary the thermalenergy input to said air stream, including synchronizing meansinterlocking the operation of said control means and said transmissionto match the heat input to the blower speed.

2. A dryer as defined in claim 1, said control means comprising a switchhaving relatively movable switch contacts and a movable actuatingelement for effecting relative movement of said switch contacts, andsaid synchronizing means comprising a mechanical driving connection tosaid transmission for efiecting shifting of said transmission uponmovement of said actuating element.

3. A dryer as defined in claim 1, said transmission comprising a drivinghub connected to said blower and having driving portions of differentdiameter, drive means interconnecting said driving hub and said motor,and said control means including an actuating device for shifting saiddrive means from one of said driving portions to another.

4. A clothes drying appliance comprising a blower having a pulley hubwith multiple pulley grooves of different diameter, a pulley beltshiftable between said grooves to drive a stream of air at differentselected rates of volume flow, heating means fortemperature-conditioning an air stream directed through a treatment zonein the drying appliance at different selected rates of heat input, and acommon control means for the pulley belt and the heating meanscomprising, a switch having a rotatable shaft, mechanical pulley beltshifting means, an electrical heater control means, means mechanicallyinterconnecting said shaft and said belt shifting means, and meanselectrically interconnecting said heater control means and said switch,whereupon actuation of said common control means will simultaneouslychange the heat input and the blower speed, thereby to match a selectedheat input to a selected blower speed.

5. In a clothes drying machine including a heat source and an airtranslation means driven by motor means through belt means extendingfrom said motor means to said air translation means, an improved controlapparatus comprising, pulley means having a plurality of belt-retaininggrooves and cooperating with said air translation means and said beltmeans to rotate said air translation means at different preselectedspeeds, belt shifting means for moving said belt from one of saidgrooves to another to effect an increase or decrease in speed of saidair translation means, means for varying the heat input from said heatsource at different preselected rates and a common control device forsimultaneously controlling and matching the heat output of the heatsource and the speed of the air translation means.

6. In a clothes drying machine as defined in claim 5, said commoncontrol device comprising switch means for increasing or decreasing theheat output of said heat source.

7. In a clothes drying machine as defined in claim 5, said commoncontrol device comprising switch means for increasing or decreasing theheat output of said heat source and control means for simultaneouslyactuating said belt shifting means and said switch means.

8. In a clothes dryer for drying fabrics including means defining adrying zone for receiving damp fabrics to be dried, the improvementcomprising:

air translation means for moving air through said drying zone,

drive means including a transmission having means for varying the speedratios for driving said air translation means at different rates of airflow,

a plurality of heaters for heating air moving through said drying zone,

circuit means including switch means for selectively energizing saidheaters to vary the heat input,

and common control means interconnected to said transmission and to saidswitch means for simultaneously effecting a coordinated change of heatin put and air flow through said drying zone.

References Cited by the Examiner UNITED STATES PATENTS 2,198,420 4/1940Winton 74--217 2,288,227 6/1942 Clapp 3487 2,398,880 4/1946 Broglie 34452,621,423 12/ 1952 Clark 3445 2,742,793 4/1956 Askren et al 742172,798,302 7/1957 Reiter 3445 2,819,540 1/1958 Toma et a1. 3445 2,825,1463/1958 Kostelich 3445 WILLIAM F. ODEA, Primary Examiner. NORMAN YUDKOFF,Examiner.

8. IN A CLOTHES DRYER FOR DRYING FABRICS INCLUDING MEANS DEFINING ADRYING ZONE FOR RECEIVING DAMP FABRICS TO BE DRIED, THE IMPROVEMENTCOMPRISING: AIR TRANSLATION MEANS FOR MOVING AIR THROUGH SAID DRYINGZONE, DRIVE MEANS INCLUDING A TRANSMISSION HAVING MEANS FOR VARYING THESPEED RATIOS FOR DRIVING SAID AIR TRANSLATION MEANS AT DIFFERENT RATESOF AIR FLOW, A PLURALITY OF HEATERS FOR HEATING AIR MOVING THROUGH SAIDDRYING ZONE, CIRCUIT MEANS INCLUDING SWITCH MEANS FOR SELECTIVELYENERGIZING SAID HEATERS TO VARY THE HEAT INPUT, AND COMMON CONTROL MEANSINTERCONNECTED TO SAID TRANSMISSION AND TO SAID SWITCH MEANS FORSIMULTANEOUSLY EFFECTING A COORDINATED CHANGE OF HEAT INPUT AND AIR FLOWTHROUGH SAID DRYING ZONE.